Loading dock shelter with semi-rigid curtains

ABSTRACT

In order to provide a loading dock shelter with an effective seal, the shelter is provided with a side curtain that is semi-rigid. The relative stiffness of the curtain allows it to be supported along a vertical edge, while a distal vertical edge of the curtain can be cantilevered for sealing against the side of a truck. The curtain has sufficient flexibility and resilience to at least partially seal against the truck without having to rely on compressible foam. In some cases, the semi-rigid curtain is attached to a side frame by way of a sliding connection that allows for differences in thermal expansion between the curtain and the frame. A relatively pliable corner seal helps seal a gap between the side curtain and an adjacent head curtain.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The subject invention generally pertains to loading dock shelters and more specifically to an enhanced sealing member for such a shelter.

[0003] 2. Description of Related Art

[0004] Trucks and other vehicles typically back up against a loading dock or doorway of a building to facilitate loading and unloading of the vehicle's cargo. Often a dock shelter is installed around the doorway to help shelter the area between the perimeter of the doorway and the rear of the vehicle. If left unsheltered, air gaps between the outer wall of the building and the back of the vehicle might allow the outside weather to increase the building's heating or cooling load, allow rain and snow to enter the interior of the building, or simply subject the inside dock workers to an uncomfortable draft while they service the vehicle.

[0005] Dock shelters usually include a framework that extends one to three feet outward from the face of the building wall. In some cases, pliable curtains hang from the framework and are situated to drape over the top and either side of a vehicle parked under the shelter. Such curtains are generally not self-supporting and tend to be rather limp, which can create a poor appearance. Lateral reinforcement of such curtains may be provided by including stays or other stiffeners. While this may improve appearance and/or sealing characteristics, it also requires additional components and labor to assemble. Further, while shelters may be adequate in milder climates, additional or alternate sealing may be required where weather conditions are more severe.

[0006] Thus, some loading docks are provided with dock seals made of a resiliently compressible foam pad. As a truck backs into the dock and against the seal, the foam pad compresses to conform to the contour of the rear edges of the truck. Although effective, such seals can be expensive, as they comprise an assembly of components. The foam pad usually needs a tough outer cover to protect the pad from wear and to prevent the pad from absorbing water and dirt. A cover should be tough to resist wear, yet pliable to allow the foam pad to compress. Unfortunately, some of the toughest materials are not very pliable, and vise versa. So, a compromise is often needed in selecting a cover with an optimum combination of toughness and pliability.

[0007] Consequently, a need exists for a dock shelter that provides a more positive seal than current shelters, yet is more economical than conventional dock seals.

SUMMARY OF THE INVENTION

[0008] In order to provide a dock shelter with a more effective seal, a dock shelter is provided with a side curtain that is semi-rigid. The relative stiffness of the curtain allows it to be supported along a vertical edge, while a distal vertical edge of the curtain can be cantilevered for sealing against the side of a truck. The curtain has sufficient flexibility and resilience to at least partially seal against the side of a truck without having to rely on compressible foam. In some cases, the semi-rigid curtain is attached to a side frame by way of a sliding connection that allows for differences in thermal expansion between the curtain and the frame.

[0009] In some embodiments, a dock shelter is provided with a head curtain attached to a head frame by way of a sliding connection that allows for differences in thermal expansion between the head frame and the head curtain.

[0010] In some embodiments, a corner curtain covers the gap between a side curtain and a head curtain with the corner curtain being more pliable than the side curtain or the head curtain.

[0011] In some embodiments, a sliding connection between a side curtain and a side frame is created by providing the curtain with vertical slots used for anchoring the curtain to the frame.

[0012] In some embodiments, the dock shelter includes a vertically elongated side curtain of sufficient rigidity to be cantilevered from an anchored vertical edge out to a distal vertical edge.

[0013] In some embodiments, the distal vertical edge of a side curtain is curved about a vertical axis to help prevent the edge from catching on a vehicle as the vehicle leaves the dock shelter.

[0014] In some embodiments, metal stays provide a plastic side curtain with greater rigidity and resilience.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a front view of one embodiment of a dock shelter with a semi-rigid side curtain.

[0016]FIG. 2 is a side view of the dock shelter of FIG. 1 showing a vehicle backing into the shelter.

[0017]FIG. 3 is the same as FIG. 2, but showing the vehicle having already backed into the shelter.

[0018]FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 3.

[0019]FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 3.

[0020]FIG. 6 is a cross-sectional view taken along line 6-6 of FIG. 1.

[0021]FIG. 7 is a cross-sectional view taken along line 7-7 of FIG. 6.

[0022]FIG. 8 is a cross-sectional view similar to FIG. 6, but of another embodiment.

[0023]FIG. 9 is a cross-sectional view similar to FIG. 6, but of another embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0024] Referring to FIGS. 1-3, a dock shelter 10 installed around a doorway 12 of a loading dock 14 includes semi-rigid side curtains 16 and 18 that help provide a weather seal between the rear sides of a vehicle 20 and a wall 22 of a building. To help seal along a rear upper surface of vehicle 20, a head curtain 24 (similar to side curtains 16 and 18 or of another design) can be installed along an upper portion of dock shelter 10.

[0025] To support the curtains, shelter 10 includes a frame 26 comprising a head frame 28, a right side frame 30 and a left side frame 32 that respectively support curtains 16, 18 and 24. Frame 26 attaches to wall 22 and supports the curtains in an offset relationship to the face of wall 22. The offset relationship allows vehicle 20 to back into shelter 10 and underneath head frame 28. As vehicle 20 backs into shelter 10 and against bumpers 30 (i.e., moves from the position of FIGS. 2 and 4 to that of FIGS. 3 and 5), the sides and top of vehicle 20, being larger than the inner dimensions of shelter 10, deflect the inner edges of curtains 16, 18 and 24 backward and inward. The inner edges of the curtains thus provide a sliding seal against the rear sides and roof of vehicle 20.

[0026] To create the sliding seal, curtains 16, 18 and 24 can be moved from their standby positions of FIGS. 1, 2 and 4 to their operative sealing positions of FIGS. 3 and 5, as vehicle 20 backs into shelter 10. Although such curtain movement can be provided by using hinges to attach the curtains to frame 26, a preferred approach is to make curtains 16, 18 and 24 of a material having sufficient flexibility to resiliently bend without the use of hinges. However, the curtain material preferably still has sufficient rigidity to allow left side curtain 16 to be cantilevered from a proximal edge 36 (attached to side frame 32) to a distal edge 38 (adapted to slidingly engage vehicle 20). The same applies to right side curtain 18. Head curtain 24, as mentioned earlier, can be of a similar construction or of another design entirely. For the sake of simplicity, dock shelter 10 will be described primarily with reference to left side curtain 16, with right side curtain 18 and head curtain 24 having similar features.

[0027] In some embodiments, side curtain 16 is made of ⅛-inch thick high molecular weight polyethylene. Although other materials and thickness can be used, this material in particular provides several benefits. The relatively high density and other properties of high molecular weight polyethylene makes it more resistant to water, dirt and abrasion than many foam materials, and thus the material does not require a protective cover. The rigidity of polyethylene not only provides a neat, sag-free appearance, but also allows side curtain 16 to be cantilevered from proximal edge 36, rather than being suspended from its top edge. Supporting curtain 16 from the side allows distal edge 38 more freedom of movement, especially near the top of curtain 16, thus distal edge 38 can effectively seal against vehicle 20 over a broader range of curtain deflection.

[0028] A curtain made of polyethylene alone may have sufficient resilience to return from its operative position to its standby position, especially if gravity urges the curtain to its standby position, as is the case with head curtain 24. Nonetheless, side curtain 16 may include several spring-steel stays 40 that improve the curtain's overall resilience. Stays 40 can be attached to side curtain 16 by any one of a variety of fasteners 42 including, but not limited to, screws or rivets. Fasteners 42 are preferably attached at opposite ends of each stay 40 to allow a central portion of stay 40 to bend away from the plastic portion of curtain 16 as curtain 16 deflects about a vertical axis 44 (FIG. 5).

[0029] To smoothed the movement of side curtain 16 as a departing vehicle allows curtain 16 to return to its standby position, distal edge 38 is curved about a vertical axis 46, as shown in FIG. 4. With distal edge 38 being curved rather than sharp and straight, distal edge 38 is less likely to catch on the side of vehicle 20 as vehicle 20 moves out from within dock shelter 10.

[0030] In some cases, side frame 32 and side curtain 16 have different coefficients of thermal expansion. For instance, curtain 16 being made of polyethylene has a greater coefficient of thermal expansion than a side frame being made of wood. To accommodate this difference, a sliding connection 48 can be used to attach side curtain 16 to side frame 32, as shown in FIGS. 1, 6 and 7. For example, sliding connection 48 can be provided by screws 50 protruding through elongated slots 52 in curtain 16 and screwing into side frame 32. The shank of screws 50 form vertically fixed posts which extend into the elongated slots 52. One will appreciate that other vertically fixed posts could achieve the same function—such as posts formed in the side frame or otherwise affixed thereto. In the case of screws 50, they serve the additional advantageous function of limiting movement of the curtain away from the wall due to the presence of the screw heads. A stand-off bushing 54 can be added to help prevent the head of screw 50 from being over tightened against curtain 16. If bushing 54 is used, the shank of screw 50 fits through bushing 54, and the bushing is a part of the vertically fixed post as a sliding fit is provided between an outer diameter of bushing 54 and the width of slot 52. For the illustrated dock shelter, side curtain 16 includes one point of attachment 56 that is relatively fixed, rather than being a sliding connection. The fixed point ensures that any expansion of side curtain 16 will be from that point. In other words, with point 56 being near the top of side curtain 16, the bottom of curtain 16 will move more than the top, as curtain 16 expands and contracts vertically. Alternatively, the curtain adjacent point 56 could have a slot as well, but having a smaller vertical extent than the other slots and positioned such that the screw or vertically fixed post would normally be disposed at the top of that slot.

[0031]FIG. 8 illustrates another example of a sliding connection 48′. Here, a sliding fit exists between slot 52 and screw 50; however, an angle member 58 attached to a side frame 32′ prevents the head of screw 50 from being tightened against curtain 16. Thus, bushing 54 can be eliminated.

[0032] In another example of a sliding connection 48″, shown in FIG. 9, a side curtain 16′ includes a ridge 60 running along a proximal edge 36′ of curtain 16′. An angle member 62 with an added lip 64 then captures ridge 60 to limit the curtain's sideways movement (i.e., perpendicular to the length of proximal edge 36′). Thus, ridge 60 and angle member 62 inhibit curtain 16 from completely separating from a side frame 32″ and member 62. However, angle member 62 provides ridge 60 with enough clearance to allow some sliding movement between curtain 16′ and frame 32″ for thermal expansion in a direction parallel to ridge 60. Ridge 60 can be an integral extension of curtain 16′ or can be an added piece attached using an adhesive or a mechanical fastener. A mechanical stop, such as a fastener or some other obstruction, may be added to limit how far ridge 60 can slide within angle member 62.

[0033] To help cover a gap 64 between side curtain 16 and head curtain 24, a corner curtain 66 can be installed at each upper corner of dock shelter 10. Comer curtain 66 can be especially useful, as gap 64 increases in size as the other curtains deflect from their standby positions to their operative positions. As gap 64 widens, its shape changes significantly with its defining edges being distorted three-dimensionally. To maintain gap 64 covered under such distortion, corner seal 66 overlaps both head curtain 24 and side curtain 16. Also, corner curtain 66 is preferably more pliable than curtains 16 and 24 to effectively conform to the changing shape of gap 64. In some embodiments, corner curtain 66 is a relatively lightweight vinyl attached to frame 26, such that corner curtain 66 is in front of side curtain 16 and behind head curtain 24, or conversely, in front of head curtain 24 and behind side curtain 16.

[0034] Although the invention is described with reference to a presently preferred embodiment, it should be appreciated by those skilled in the art that various modifications are well within the scope of the invention. Therefore, the scope of the invention is to be determined by reference to the claims that follow. 

I claim:
 1. A dock shelter adapted to provide at least a partial seal between a vehicle and a wall of a building, comprising: a side frame mountable to the wall and being vertically elongated; a side curtain having a proximal edge coupled to the side frame and a distal edge adapted to engage the vehicle; and a sliding connection that couples the proximal edge to the frame, wherein the sliding connection allows vertical thermal expansion of the side curtain relative to the side frame.
 2. The dock shelter of claim 1 wherein the sliding connection comprises at least one vertical slot in the side curtain and at least one vertically fixed post fixed relative to the side frame and received within the at least one slot.
 3. The dock shelter of claim 2, further comprising a plurality of metal stays attached to the side curtain to help bias the side curtain to the standby position.
 4. The dock shelter of claim 2, wherein the distal edge curves about a second vertical axis.
 5. The dock shelter of claim 1, wherein the proximal edge has a plurality of vertically elongated slots that facilitate the sliding connection.
 6. The dock shelter of claim 5, further comprising a plurality of fasteners extending through a plurality of bushings, which in turn extend through the plurality of elongated slots, wherein the plurality of bushings each have a length that helps prevent the plurality of fasteners from being over tightened against the side curtain.
 7. The dock shelter of claim 1, further comprising: a head frame mountable to the wall and being horizontally elongated; a head curtain suspended from the head frame; and a corner curtain bridging a gap between the head curtain and the side curtain.
 8. The dock shelter of claim 7, wherein the corner curtain is more flexible than the side curtain and the head curtain.
 9. The dock shelter of claim 7, wherein the corner curtain includes a first portion that overlaps the side curtain and a second portion that overlaps the head curtain such that the side curtain is closer to the wall than the first portion but the second portion is closer to the wall than the head curtain.
 10. A dock shelter adapted to provide at least a partial seal between a vehicle and a wall of a building, comprising: a side frame mountable to the wall and being vertically elongated; a side curtain having a proximal edge coupled to the side frame and a distal edge adapted to engage the vehicle; and a first sliding connection that couples the proximal edge to the frame, wherein the first sliding connection allows vertical thermal expansion of the side curtain relative to the side frame; a head frame mountable to the wall and being horizontally elongated; a head curtain suspended from the head frame; and a second sliding connection that couples the head curtain to the head frame, wherein the second sliding connection allows horizontal thermal expansion of the head curtain relative to the head frame.
 11. The dock shelter of claim 10, wherein the distal edge curves about a vertical axis.
 12. The dock shelter of claim 10, further comprising a corner curtain bridging a gap between the head curtain and the side curtain.
 13. The dock shelter of claim 12, wherein the corner curtain is more flexible than the head curtain and the side curtain.
 14. The dock shelter of claim 10, wherein the first sliding connection comprises at least one vertical slot in the side curtain and at least one vertically fixed post fixed relative to the side frame and received within the at least one slot.
 15. A dock shelter adapted to provide at least a partial seal between a vehicle and a wall of a building, comprising: a side frame mountable to the wall and being vertically elongated; a side curtain having a proximal edge coupled to the side frame and a distal edge adapted to engage the vehicle; a head frame mountable to the wall and being horizontally elongated; a head curtain suspended from the head frame; and a corner curtain bridging a gap between the head curtain and the side curtain, wherein the corner curtain is more pliable than the side curtain.
 16. The dock shelter of claim 15, wherein the corner curtain is more pliable than the head curtain. 